Figure 2.

Surface models adopting periodic and cluster approaches. Periodic slab models for the (100) pyrite FeS₂ surface (A), α-quartz hydroxylated (010) surface (B), montmorillonite clay (C), and anatase (101) TiO₂ surface (D). The unit cell along one direction is shown in blue. Cluster models for surfaces of (Ni,Fe)S vioralite (E), silica (F), the octahedral sheet of kaolinite (G), and an acidic aluminosilicate (H). For this latter structure, the atoms represented in balls belong to the high-level zone while the atoms in sticks to the low-level zone in Our Own N-layered Integrated Molecular Orbital and Molecular Mechanics (ONIOM) calculations.